Hydraulic jack



g- 1929- T. w. PEDERSEN 1,725,720

HYDRAULIC JACK Filed March 22. 1927 4 Sheets-Sheet l @zwe s Aug. 20, 1929. I 1: w, PE E 1,725,720

HYDRAULIC JACK Fiied March 22,1927 4-shee'ts-sheet 2 20, 1'. w. PEDERSEN 7 1,725,720

HYDRAULIC JACK Filed March 22, 1927 4 Sheets-Sheet 3 l'm'mmnm g l r I freoerzZbrn' Aug; 20, 1929. T. w. PEDERSEN 1,725,720

' HYDRAULIC JACK Filed March 22, 1927 4 Sheets-Sheet 4 4 ZW A) 66 av Even/fork z/l a/wwwa af'd m Patented Aug. 20, 1929.

UNITED STATES 1,725,720 PATENT OFFICE- j THOMAS W. PEDERSEN, OF NEW YORK, N. Y., ASSIGNOR TO THE OIL JACK COMPANY,

\ INC., 015 NEW YORK, N. Y., .A CORPORATION OF NEW YORK.

HYDRAULIC JACK.

Application filed March 22, 1927. Serial No. 177,369.

in conjunction with a plunger entirely sepa-' rate therefrom.

Another object of the invention is to provide means whereby the plunger is self- ,aligning with respect to the packing members at the top of the cylinder in which the plunger operates.

Another object of the invention is toprovide means whereby the piston packings may be easily removed from the cylinder for replacement or repair.

A further object of the invention is to provide a 'novelform of valve controlling the flow offluid in the jack, the valve construction reducing the cost of manufacturing these parts by avoiding the necessity for.

close machine work in fitting the parts in the jack body.

A to provide novel means for connectingthe jack cylinder with the reservoir whereby the eii'ective height of the jack cylinder is increased Without increasing the overall dimensions of the jack- The invention also contemplates the provisionof a novel form of swivel head hav-. ing certain desirable self-adjusting features as hereinafter described.

The above and other useful ends appear-- ing hereinafter ll accomplish by means of the construction and design illustrated in the atesitached drawings, in which:

Figure 1 is aside elevation of a jack made in accordance with my invention;

-Big. 2 is a section on the line2'2, Fig. 1;

Fig. 3 is a section on the line 3.3, Fig. 2;

Fig. 4 is a horizontal section on the line d4,JFig. 1, and

Fig. 5 is a, fragmentary horizontal section on the line 55, Fig. 1.

Referring to the drawings, thefiack in a preferred form comprises a substantially and .the principal object of projecting still further object of the invention is bottle-shaped casing 1 having at one side an integral handle 2. Thecasing 1 comprises a main cylinder 3, and in the lower part a reservoir chamber 4, said reservoir extending around the lower part of the cylinder. The cylinder 3 atv the bottom of the casing 1 is countersunk, and this recess is threaded for reception of a screw plug 5, which closes the bottom of the cylinder 3 except for certain passages establishing communication between the cylinder 3 and the reservoir, and a pump cylinder, all as hereinafter described. 4

At: oneside of the main" cylinder 3 is a pump cylinder 6, this. being formed by a tubular cylinder member, 7 threaded into I the casing 1 as shown in Fig. 2. The top-of the threaded aperture which receives the member 7 is countersunk to form a packing box in which the packing 8 is retained by a follower 9 which itself isforced downand held in place by a flange 11 at the top of the member 7 and the member 7 itself is countersunk at the top to, form a stuffing; box through which. the pump plunger 13 extends and which includes a follower 12 which is threaded into the recess above the packing. The pump plunger as shown in Figs. 1 and '2 is connected through a link 14 with a lever 15 pivotally mounted upon a stub shaft 16 from a boss 17 on the casing 1, said lever 15 having a socket 18 for reception of a suitable'operating lever. By oscillating the'lever 15, the plunger 13 is reciprocated in its cylinder, the stroke of the piston being limited by a pair of lugs 19, 19 on the lever which coact with a fixed teat 21 on the casing. Suitable packing elements 22 are secured to the bottom of the plunger by means of a set screw 23, and the lower end of the cylinder member 7 rests on a seat 24 in the casing, the joint between the cas-' ing and the member 7 being sealed at this point by a gasket 25. i

The lower end of the pump cylinder 6 communicates with the reservoir 4: through a vertical channel 26 and a horizontal channel 27. This -channel 27 opens into an enlarged chamber 28 communicating with the channel 26, see Fig. 4, which chamber houses acheck 105 "valve comprising a hall 29 which is held to "shoulder 34fof the plunger 33 and the inner face of a plug 35 threaded into the outer end of the chamber 28. The plug- 35 is recessed from its inner end asindicated at 36 for' reception of the outer" end of the plunger 33 whereby the latter is permitted tomove back when the ball ,29 is forced from its seat. It'will be understood that when the valve is, closed, the assage'26 is shut off from the passage 27, tl ereby breaking communication between the pump cylinder and the reservoir. When the pump plunger, however, is raised,the check valve 29 permits flow of oil or other actuating medium from the reservoir 4 into the' pum cylinder, backflow, however, being prevente The pump cylinder is also connected through horizontal passages 37 and 38 with the bottom of the main, cylinder 3. As

shown in Fig. 4,,the channel 37 communicates with the vertical channel 26 entering the pump cylinder, and the channel 37 has, Q an enlarged part 39 constituting a chamber for a check valve 41 permitting flow from the pump oylinderto the main cylinder, but preventing flow in the opposite direction. The valve 41 is in the form of a ball which is normally held to a seat 42 by a spring 43 operating through a plunger 44. The spring is confined between the head 45 of said plunger and the inner face of a plug 46 threaded into theouter end of the. chamber 39, the plug bein recessed in its inner face as indicated at 4 for the reception of the outer end of theplunger- 44, this permitting longitudinal movement of the plunger against the spring pressure when the valve 41 is forcedback. It will now be seen. that with the downward movement of the plun- -ger 13in the pump cylinder, any oilthat may have been drawn into this cylinder is forced through the channels 37 and 38 into 4 the bottom of the main cylinder 3.

'Within the main cylinder 3- is a piston 47,

this piston being comparatively small andhaving thereon a threaded stud 48 by means ofwhich, and a nut 49, suitable packing elements 51 may be attached to the under side of the piston. .The casing 1 at the top of the main cylinder 3 is'countersun'k and threaded. for reception of a packing gland 52 and fol-' packing may 'terial 54. Through this packing box lower 53 between which is held rojects into thecylinder a plunger 55 whic is entirely independent of the iston 47 but which is forced upwardly in t e cylinder by the piston when the latteris advanced therepressure created ashereinbefore set forth.

The outer end of the plunger 55 is ada t ed for reception of a shoe 56, the end of t e plunger being rounded and the shoe 56 havmga correspondingly rounded recess into which the rounded topof the plan er is adapted-to fit, forming thereby a b l and socket joint betweenthese -part's and providing for free self-adjustment of the shoe 56 under misaligned load conditions. The shoe 56 "is held on the plunger 55 by means of a split in 57 so arranged withrespect to the roun ed or hemispherical contacting sur faces of the plunger and the shoe as to permitosc'illation of theshoe about the axis of the said pin. The pin 57 extends through an aperture 58 in the plunger, and this aperture is formed with a double reverse taper, as shown-in Fig. 3, which permits a rocking I movementof the pin to complete the universal connection between thea shoe and the plunger.

As described above, when the pump,

plunger 13 is reciprocated, actuating fluid is drawn from the reservoir 4 and forced into the main cylinder 3 below the piston 47. The latter accordingly is forced upwardly, and by engaging the lower end of the plunger 55 elevates the latter.

To permit return of the piston 47. to the bottom of the cylinder, a connection is 66 in the casing. The chamber 66 communicates through a short passage 67 with "the passages 59 and 61, the ball valve 62 being seated in the bottom of the said passage 67. v i Intermediate the inner end of theset screw '64 and the ball 62 is a plunger 68, this plunger being a separate element and independent, except for operative contact, from the ball 62 and the 'set' screw 64. The bottom of the chamber 66 forms a box for pack- 'ing 69, this being compressed around the plunger 68 by the bushing 65. The valve 62- normally is. closed, but when the plunger 47 is to be returned to the bottom'of the previously described, the valve may be opened by backing off the set screw 64'to permit the-plunger 68 and the bal 62 to move outwardly and thereby permit passage of the fluid from the' mam cylinder 3 It will 'be noted that-the joint between the 'plug 5 and the casing 1 is sealed by means of a gasket 71, this gasket being com-.

cylinder-following elevation 'inthe manner I through thgpassages 59 and 61 to the reser-. voir.

paratively narrow so asf'to leave a space between thecasing and the bottom of the plug 5. It is with this space that both the channel 38 and the passage 59 communicate, as shown in Figs. 3 and 4;. By utilizing the clearanceleft by thegasket between the two parts in this manner for the connections between the main cylinder, the pump cylinder and the reservoir, the efiective height of the cylinder 3 is maintained at a maximum. It Will further be noted that with the construction described, the packing of the piston 47 is accessible for removal and replace ment by merely unscrewing the plug 5, no special tools being required for this purpose.

In the event of leakage of the actuating fluid past the piston 47, the leakage will be reservoir 4 automatically returned to the through a passage 7 2 at the to of the casing which communicates with tie top of the cylinder 3 and a communicating or cross passage 73 communicating with the reser; voir 4.

The operation of the device will be. readily understood from the foregoing description,

the jack being placed in a suitable position with the shoe 56 engaging the load with the piston 47 and plunger 55 depressed in the cylinder as shown in the drawings. The pump is actuated as described to withdraw the actuating fluid from the reservoir 4 and project it into the cylinder 3 below the pis-- ton 47. The piston 47 being forced up in the'cylinder engages the lower end of the plunger 55 and brings pressure to bear upon the load. c

By reason of the self-adjustable feature of the shoe 56, the components of theoperating pressure which are angular to the axis of the plunger 55, are reduced to a minimum, and by reason of the independence of the plunger from the piston 47, there is no tendency for the piston, in spite of its comparatively narrow bearing on the cylinder Wall, to score or dig the side of the cylinder.

This separate construction of piston and plunger also works a material saving in the cost of manufacture by reason, first, that no exact alignment is required between the cylinder and the threaded bushings 52 and 53 at the top, and secondly, because the plunger may be formed for example of a piece of cold rolled steel, while the piston is extremely simple and easy to manufacture. It will be apparent that when necessary, the plunger 55 may be withdrawn completely from the cylinder without affecting the operation of the jack or disturbing the operat ing parts. A further manufacturing advantage is obtained in the form of the valve controlling the How of the actuating fluid from the main cylinder to the reservoir, for by utilizing the loose piston 68, accurate machine work and its attendant cost is avoided.

I claim:

1. In a hydraulic jack, the combination with a cylinder, of a piston confined to said the bore of the cylinder separate from cylinder,

cylinder, a plunger of smaller diameter than the bore of the cylinder separate from but actuable by said piston projecting from the cylinder, a reservoir, a pump, and Valvecontrolled passages connecting the said pump with the cylinder and with the reser- V011.

2. In a hydraulic jack, the combination with a cylinder, of a piston confined to said cylinder, a plunger of smaller diameter tllljtll ut actuable by said piston, a stuffing box at the top of the cylinder through which said plunger projects, a reservoir; a pump, and valve-controlled passages connecting the said pump with the cylinder and with the.

reservoir.

' 3. In a hydraulic jack, the combination with a cylinder, of a piston confined to said a plunger of smaller diameter than the bore of the cylinder separate from but actu-able by said piston and of lesser diameter than the said cylinder, a guide for the plunger at the top of'said cylinder through which the plunger extends, a reservoir, a pump, and valve-controlled passages connecting the said pump with the cylinder and *with the reservoir.

4;. In a hydraulic jack, the combination with a cylinder, of a.piston confined to said cylinder, a plunger of smaller diameter than the bore of the cylinder separatefrom but actuable by said piston, a stuffing box at one end of said cylinder through which the plunger extends, said stufl'mg box including a bushing securedin the open end of the cylinder and constituting a guide for the plunger, a reservoir, 3. pump, and valve-controlled passages connecting the saidpump with the cylinder and with the reservoir.

5. In a hydraulic'jack, the combinationv with a cylinder, said cylinder being countersunk at one end, of a plug insertable in the countersunk recess to close the end of the cylinder, a piston confined to the cylinder and adapted to be withdrawn from the cylinder through said countersunk end when said plug is removed, and a plunger of smaller diameter than the bore of the cylinder separate from but actuable by said piston projecting into the other end of said cylinder.

6. In a hydraulic jack, the combination with a cylinder having a countersunk recess at bnc end, of a plug insertable in said recess to close the cylinder, a piston in said cylinder including packing elements, means for securing said packing to the. piston accessible through said countersunk end of the cylinder, and a plunger of smaller diameter than the bore of the cylinder separate from but actuable by said piston and projecting through the other end of the cylinder, a reservoir, a pif'mp, and valve-controlled pasthe main cylinder and including a cylinder sages connecting the said pump with the cylinder and with the reservoir.

7. In a'hydraulic jack, the combination with a casing including a main cylinder, of apiston operative in said cylinder, a plunger oi 'smaller diameter than the bore of the cylinder separate from but actuable by the piston and projecting from one end of the cylinder, a reservoir chamber in said casing, and a pump operatively connected with the said reservoir chamber and with member insertable through an opening in said casing, said opening being countersunk for reception of packing material surrounding the piston,-means on the cylinder member for retaining the said packing in position, means forsealing the oint between the inner end of the cylinder member and the pump casing, a plunger in the cylinder projecting from the outer end thereof, said cylinder member having at its. outer end a countersunk recess for reception of packing surrounding the plunger, and a bushing se- .cured in the outer-end ofsaid countersunkrecess and retaining the packing in place.-

8. .In a hydraulic jack, the combination with a casing including a main cylinder countersunk at one end, of a plug adapted to be inserted in said'recess to close that end of the cylinder, anarrow gasket sealing the joint between the plug and the casing and forming a space between the inner face of the plug and the casing directly communieating with the cylinder, a reservoir chamber withinthe casing, a pump, and valve-' a piston operative in the cylinder, a'plunge'r.

of smaller diameter than the bore of they cylinder separate from but actuable bythe piston and projecting from-one end of the cylinder, areservoir chamber in said casing, a pump, and valve-controlled passages conthe main cylinder with the reservoir chamber, and a manually-operated valve controlling said last -named passage and comprising a valve element adapted when seated to close the passage, a member threaded in the.

'50 necting the pump with the reservoir and with the cylinder, a passage also connecting,

casing whereby pressure may be exerted upon the valve to hold it to its seat, and a separate cylindrical member interposed between the valve'and the threaded element,-

and a stufiing box accessiblefrom the outside of the casing and providing for a packed joint around said-cylindrical member.

said casing and operatively connected with 10.'In a hydraulic jack, the combination with a casing including a main cylinder anda reservoir chamber, of a pump mounted in Y the main cylinder and =with the reservoir chamber, a piston operative-iii the main cylinder, and a plunger of smaller diameter.

than the bore-of the cylinder separate from but actuable by the piston and projecting from one end of said cylinder, the outer end of said plunger being formed on the arc of a circle, a head having a correspondingly formed recess and adapted to fit adjustably Y on the a rounded enclA versely tapered tow rds the center, .and a pin extending through said opening and of said plunger, said plunger having a ransverse opening re.-'

through apertures in said head, the trans verse opening being soarranged that the axis of the pin extends through a point ooriresponding with the center of the rounded end of said plunger whereby the head is universally adjustable with respect to the plunger, THOMAS w. PEDERSEN. 

